For these experiments you will need the kit listed on the contents page in your box. You will also need the following –
- Empty bottle
- Sticky tape (optional)
Cotton reel car
You need your small stick (two of these are spares), long stick, cotton reel and elastic band.
- Break the small stick at both ends (don’t snap it) so it makes a U shape – like a square with 1 side missing – like this PHOTO.
- Put the elastic band over the broken stick and thread the band through the middle of the cotton reel.
- The small stick should hold the elastic band in place. Like this –
- Place the long stick through the other end of the elastic band.
- Wind up the end of the elastic band with the long stick and let it go, watch your cotton reel car move! It should look like this PHOTO.
If the car isn’t moving, try pulling the stick away from the cotton reel to stretch the elastic band and reduce friction.
The reason your car moves is because of ENERGY! Here is Chemical Cress to tell us a little more about energy –
Contact and non contact forces
We use forces all the time. Try and think of some forces you have used today. Have you pulled a door open? Or kicked a football? Maybe you have rubbed your hands together to warm them up. All of these are forces! But did you know that there are different types of forces? Some forces are CONTACT forces which means that objects must touch each other to make a force, such as your hand pushing a door. This includes a force caused by air movement such as air resistance or blowing. NON-CONTACT forces mean that objects do not need to touch to produce a force (e.g. gravity, magnetic force, electrical force).
- Take the ball from your ball blowing pipe, or any ball will do.
- Try and move the ball using as many contact forces as you can.
- How many did you use?
- Now try again, but this time you can only use non-contact forces!
- It should be a bit harder to think of these, how could you use gravity to move the ball without touching it first?
Ball blowing pipe
This experiment is a good chance to test one of your contact forces!
- Put the ball in the basket at the end of your ball blowing pipe.
- Put the other end in your mouth and gently blow.
- Can you get the ball to hover above the pipe?
- How high can you get it before the ball falls?
Your blowing force is having to fight against the force of gravity and also air pressure around the ball to keep it hovering! Here is *scientist* to tell us a bit more about this. It is all to do with a scientist called Bernouille!
Air pressure trick
For this experiment you will need an empty bottle, any size will do, and the ball from your ball blowing pipe.
- Try and put the ball into the bottle – easy!
- Try it again, but this time lie the bottle down and place the ball just inside the neck of the bottle.
- Try and blow the ball in. You can’t!
- Give it a go with different types of balls, such as a little ball of paper. Nothing works.
It’s all to do with Bernoille’s principal that *SCIENTIST* told us about before. Your bottle may look empty but it is actually full of air! This means that you can’t blow any more air into the bottle. Your ball may have blown out of the neck of the bottle, this is because you are creating fast moving air around the ball, which has low pressure. So the high pressure from inside the bottle pushes the ball out.
*This experiment should be done with an adult in an outside space*
You need your film canister (white pot and lid), fizzy tablet, some water and your stretchy alien.
- Stick the alien to the bottom of the pot, you may want to use sticky tape.
- Fill the pot half full with water.
- Find a space outside.
- *You may want a grown-up to do this bit* Drop the fizzy tablet into the water and quickly press the lid on until it clicks.
- Place it upside down (lid side down) and take two big steps back!
- It may not pop straight away, be patient. If it doesn’t pop after one minute then ask an adult to check it.
- NEVER look directly over the pot, or it could pop in your face!
- If the water leaks out, the lid may not have been on properly.
- If you have any tablet left after it pops, you can do it again by just adding more water.
When the tablet meets the water it creates a chemical reaction. This chemical reaction makes a gas called carbon dioxide! The carbon dioxide fills up the pot until there is no space left, meaning that there is lots of pressure in the pot. When the pressure gets too high, the rocket will launch!