Forces, Magnetism & Earth in Space Lessons

Forces, Magnetism & Earth in Space Lessons Lessons 1-2: Introduction to Forces Lessons 3-4: Friction Lessons 5-6: Magnetism Lessons 7-8: Air & Water Resistance Lessons 9-10: Rocket Science Lessons 11-12: Earth in Space

Forces Lessons 1-2 Introduction to forces

Question? What is a force?

What do I need to learn today? Today I will learn about forces (especially pressure). The pressure at the bottom of the oceans is so great that those foam cups got squashed…

Introduction A force is a push, pull or twist. When there is a force on an object, several things can happen: the object can speed up, slow down, change direction or change shape. Here are some examples: But there are many others (like: thrust, magnetism,tension, etc). Scientists use arrows to show the direction of the force. They measure forces in an unit called Newton (N). WEIGHT is the force that pulls an object down (because of gravity). FRICTION is the force that stops your car when you push on the brake.

Demonstration: Gravity-defying water What did I see? Why did this happen? What did I learn?

Demonstration:The Egg and the Flask What did I see? Why did this happen? What did I learn?

Demonstration: Magdeburg Spheres What did I see? Why did this happen? What did I learn?

Glossary Force: a push, pull or twist. Newton: the unit used to measure forces. Weight: the force that pulls an object down (because of gravity). Friction: the force between two objects sliding across each other. Pressure: the amount of force spread on a surface. Effervescent: bubbly.

Background Pressure is a “push” force. It is measured in newtons per meter squared (N/m2). This is because the amount of pressure depends on two things: How strong the push force is (in N). How much that force is spread out (surface area measured in m2). For example, if a lady stepped on your foot with high-heeled shoes it will be more painful than if she steps on your foot with flat shoes. This is because the high-heels puts more pressure on your poor foot. The pointy end has a smaller surface area than the flat shoe. So even when there is the same force (the weight of the lady), there is more pressure under a high heel than a flat shoe. Which would be harder: blowing into a ball with a narrow valve or a large valve?

Investigation: Effervescent Rocket Poppers Skills focus: My skills focus for the investigation is........ I will investigate the best way to make a Rocket Popper. Method 1. Break off half a tablet of Vitamin C and place it in a dry film canister. 2. Fill a third of the canister with water. 3. Place the lid onto the canister. (you should hear a “snap” sound). 4. Turn the canister upside down and place it on the table 5. Stand back! Pop!

Skill focus: Planning Independent variable The thing I will change is .. The thing I will measure is ... Dependent variable What is the effect of changing ... on the ....? My question is: When I change the (independent variable), the (dependent variable) will … My prediction (or hypothesis) I think this because … Justification Method (including any research) List of equipment: Risks:

Skill focus: Obtaining and Analysing Data Type of data: Numbers? Readings? Observations? Smells? etc. Table? How many columns? How many rows? What are the units? Where and how am I going to record this data? What type of graph could I use? Pie chart? Bar chart? Line graph? Scatter graph? There is/is not a relationship in my data. It appears that … What does my data appear to show?

Skill focus: Evaluation Did my results match my prediction? My results did/did not match my prediction. I got/I did not get valid and/or reliable data I know this because.... To make my data more valid, I need to … To make my data more reliable, I need to …. How could I improve my method so my data is more valid and reliable? I found ... anomalies. They were .... and ... they happened because ... There were anomalies in my data What other experiment could I use to test my prediction? What other question could I investigate?

Progress check Complete your progress check!

Forces Lessons 3-4 Friction

Question? How much does air weigh? Air does have weigh. 1 cubic metre (see picture) of air has a mass of approximately 1.3Kg (a bit more than a big pack of sugar)

What do I need to learn today? Today I will learn how to measure forces and about the force called friction.

Introduction Friction is the force between two objects sliding (or trying to slide) across each other. Friction makes heat. When the two objects are sliding, scientists call this kinetic (=moving) friction. When the two objects are not moving, scientists call this static (=fixed) friction. Static friction: between the chair and your bottom. Kinetic friction: between the car’s tyres and the road.

Demonstration: Newton Meters and Brass Masses What did I see? Why did this happen? What did I learn?

Background • Remember: forces can change the shape of objects. • Here the object is the spring inside the newton meter. • The greater the force, the further it will stretch and so the higher the number it will show.

Demonstration: Silk scarf and vase What did I see? Why did this happen? What did I learn?

Background There are 2 frictions here. There is friction between the scarf and the table, and friction between the scarf and vase. When you pull on the scarf gently, the force is enough cancel the friction between the scarf and the table but it is not enough to cancel the friction between the scarf and the vase. So both the scarf and vase move, but the vase stays on the cloth. When you whip the scarf down, the force is enough to cancel both frictions. So the scarf can slide off the vase and the table.

Demonstration: Measuring friction What did I see? Why did this happen? What did I learn?

Glossary Force: a push, pull or twist. Newton: the unit used to measure forces. Weight: the force that pulls an object down (because of gravity). Friction: the force between two objects sliding across each other.

Investigation: Balloon car challenge Skills focus: My skills focus for the investigation is........ You will investigate how to make the fastest balloon car (= with the least friction) Method: 1. Cut out 4 each of different sized wheels and mark a point in the centre of each wheel. 2. Insert the kebab stick into a straw and insert the stick into the centre point of the wheels 3. Attach a rectangle of card to the centre. This is where the balloon is attached 4. Attach an inflated balloon to the card 5. Release the balloon and start it with a gentle push!

Forces Lessons 5-6 Magnetism

Question? What do you know about magnets?

What do I need to learn today? Today I will learn about magnets and how they work.

Introduction • Magnetism is an invisible force. • The closer you get to the magnet, the more magnetic force there is. • Magnets have two poles, called North and South. • If you put a North and a South poles together, they attract each other (same with two South poles). • If you put two North poles together, they repel each other (same with two South poles). Like poles repel, unlike poles attract.

Introduction A magnet is usually a piece of iron metal that attracts other pieces of iron or other materials. Scientists can also make magnets out of coils of wire. The Earth is also a bit like a giant magnet.

Demonstration: Gauss gun What did I see? Why did this happen? What did I learn?

Glossary Magnet: is usually a piece of iron metal that attracts other pieces of iron or other materials. Magnetic field: a picture that shows the effect of a magnet around itself.

Investigation: Magnetic Circus Skills focus: My skills focus for the investigation is........

Theory • Compasses are magnets. The Earth is a magnet too. • When you use a compass, the North pole of the compass’ magnet will point to the South magnetic-pole of the Earth. Like poles repel, unlike poles attract. North geographical pole = South magnetic pole • It looks like the poles of the Earth are the wrong way round! • This is because there are 2 types of Earth poles: magnetic and geographical. South geographical pole = North magnetic pole

Investigation: Induced Magnetism Skills focus: My skills focus for the investigation is........ I will investigate how powerful a magnet is. Method: 1. Take the pin and stroke it 10 times (all in the same direction) across the Magnadur magnet. 2. ‘Dip’ the steel pin into a pile of paper clips 3. Count the paper clips the steel pin picks up 4. Repeat steps 1-3

Forces Lessons 7-8 Air & water resistance and buoyancy

Question? Knock Nevis is the biggest ship ever made. How does it stay afloat? This is the size of a person on this picture:

What do I need to learn today? Today I will learn why I can run faster in air than in water and explain it using forces.

Demonstration: Floating Bubbles What did I see? Why did this happen? What did I learn?

Background Air is made of different invisible gases. When you blow bubbles, the air inside and outside the bubble is almost the same. The chemical reaction in the tank makes a lot of Carbon dioxide gas. This gas makes the air in the tank “heavier” (denser) than normal air. So when you blow bubbles into it, they are “lighter” than the air around them. The force that pushes the bubbles up in the tank is called upthrust (=buoyancy). It cancels out the force that pulls bubbles down (called weight). upthrust weight

Demonstration: Water Resistance What did I see? Why did this happen? What did I learn?

Forces, Magnetism & Earth in Space Lessons