### Logic, Truth Tables and Switching Circuits Challenge

Learn about the link between logical arguments and electronic circuits. Investigate the logical connectives by making and testing your own circuits and fill in the blanks in truth tables to record your findings.

### Truth Tables and Electronic Circuits

Investigate circuits and record your findings in this simple introduction to truth tables and logic.

### Big and Small Numbers in the Living World

Work with numbers big and small to estimate and calculate various quantities in biological contexts.

# Pinhole Camera

### Equipment required

• sheet of card
• screen or large sheet of white paper
• blackout for windows
• aluminium foil, about 5cm x 5cm
• pin or sharp point
• tape
• scissors
• ruler
• candle or other light source

### Making the pinhole camera

1. Cut a square about 2cm x 2cm in the centre of the cardboard.
2. Put the foil over the square hole and tape it to the card.
3. Use the pin or point to make a small hole in the foil.

### Setting up the pinhole camera

To get an image with your pinhole camera:

1. Set it up as in the diagram and turn out all other lights.
2. You should be able to see an image of the candle flame or other light source on the screen - try different positions and see what gives the best image.